A fast-growing, aquatic or marsh-dwelling perennial herb, watercress is prized for its tangy, refreshing flavor and is often used in salads, sandwiches, and as a garnish.

The stems are hollow and can float on water or spread along the ground. The plant forms dense mats in shallow, slow-flowing water or moist soil. The leaves are tender and have a fresh, spicy aroma, especially when bruised, similar to arugula or mustard greens. The flavor is strongest in fresh, young leaves and can become more intense as the plant matures.